164 Fire

Key Idea: The controlled used of fire by early humans allowed them to eat a greater range of foods and to expand their range into darker and colder places. Just when and how early human ancestors began using fire is debated and may never be precisely known. It is likely that early fire was "captured" from the wild, e.g. from fires started by natural events such as lightning. Whatever its origin, the controlled use of fire changed the course of both physical and cultural evolution, influencing dietary range and improving survival. Possible evidence exists for the use of fire up to a million years ago, but real evidence of controlled use of fire dates back only a few hundred thousand years.

Naturally set fires were the most likely source of early fire. Burning embers may have been carried back to home sites, or the fire used where it was.

The development of the hand-drill meant early humans could make fire when and where they needed it.

A not so obvious, but important use of fire, is its use in the construction of weapons. Wooden spear tips can be hardened in fire, allowing them to be made sharper and improving their penetrative power. Rocks heated in a fire become brittle and are therefore easier to shape into tools, such as blades and spearheads. The blade also holds a sharper edge. Fire may also have been used as a hunting tool by setting fire to forests to drive out game. Fire could also be used for protection to drive off predators.

Fire provides light and can be used as a torch, allowing early humans to explore dark places such as caves. It may have helped with bonding, such as sitting around a campfire. Fire provided light and warmth at night.

Cooking is the most obvious use of fire. Cooking food makes it easier to chew and digest, releasing energy more quickly for the body to use. Fire also kills parasites and pathogens in the food. Fire can also be used to preserve food. Meat can be smoked and vegetable material can be dried.

1. List four uses of fire:

2. (a) Describe two important consequences of cooking food:

(b) Explain how cooking food provided a selection pressure for a smaller jaw and teeth:

3. Discuss the influence of fire on human cultural evolution: